In the Manchurian Strategic Offensive Operation, over 1.5 million Soviet troops invaded the Japanese puppet states of Manchukuo and Mengjiang on three fronts from positions in the Soviet Far East and the Mongolian People’s Republic. The scale, speed, and directions of the attack caught the 700 thousand strong Japanese Kwantung Army by surprise, with the Soviet pincers, supported by airborne units, penetrating deep into Manchuria. Despite this, Japanese resistance continued until 20 August - five days after Emperor Hirohito’s surrender broadcast - by which time the Soviets had reached the key cities of Mukden, Changchun, and Qiqihar.in wikipedia

On 11 August 1945, the Soviet 16th Army advanced from northern Sakhalin into the Japanese Prefecture of Karafuto in the southern half of the island, but was held back for four days by the Karafuto Fortress line. From 16 August, the Soviets began landing along the coast, seizing the ports of Toro (Shakhtyorsk), Esutoru (Uglegorsk), and Maoka (Kholmsk). A final Soviet landing at the capital of Otomari (Korsakov) on 25 August forced the main Japanese garrison to surrender, bringing an end to resistance.in wikipedia

On the evening of 14 August 1945, Japanese militarists attempted to arrest Emperor and prevent the surrender of Japan, but were caught by loyalists within the military and apprehended by morning.in wikipedia

In response to the Soviet invasion of Manchuria, Nationalist China agreed to recognize the independence of Mongolia, which had been supported by the Soviet Union since the Revolutionary era. China agreed to independence on the condition that the Soviets cease assistance to the Chinese Communist Party, but continued to respect Mongolian independence when this was not followed.in wikipedia

Japanese Emperor Hirohito read out the Imperial Rescript on the Termination of the War in a radio broadcast, announcing to the people of Japan that their government had accepted the Potsdam Declaration and agreed to unconditional surrender. The speech was the first time the Emperor had spoken to the common people.in wikipedia